Information carrier drive device provided with a double antenna

ABSTRACT

An apparatus is provided for reading an information carrier ( 1 ) which has an integrated circuit ( 21 ) and an antenna ( 22 ) coupled to the integrated circuit. The apparatus has communication means to establish communication between the integrated circuit on the disc and the apparatus. The communication means has two antennas (66,67): one which can communicate with the integrated circuit on the disc when the disc is loaded in the apparatus and one which provides communication between the apparatus and the integrated circuit on the information carrier when the disc is in the vicinity of the apparatus.

The invention relates to an apparatus for reading out an informationcarrier, which information carrier is provided with an integratedcircuit and an antenna connected to the integrated circuit, saidapparatus being provided with communication means for achieving anelectromagnetic coupling with the antenna on the information carrier.

An apparatus as described in the opening paragraph is known from U.S.Pat. No. 6,044,046. In this system, an integrated circuit (denoted chiphereinafter) is provided on an information carrier for the purpose ofstoring additional information. The information carrier may be, forexample, a disc with an optical storage unit, such as a CD or DVD. Thesediscs may be used for storing and filing comparatively large quantitiesof data in a simple manner, for example digital photos, films, and musicalbums. This information, which is protected by copyright, i.e. thedigital work, can be stored in an encoded manner on the informationcarrier so as to counteract illegal distribution. The additionalinformation stored in the chip is, for example, a decoding key withwhich the encoded digital work on the information carrier can bedecoded.

The information carrier is to be loaded into the playback apparatus ifthe digital work stored on the information carrier is to be reproduced.The playback apparatus comprises optical reading means which renderpossible the read-out of the optical storage unit.

The chip is provided with electromagnetic receiver means for obtainingthe energy necessary for the operation of the chip. Electromagnetictransmitter and receiver means are furthermore present on the chip ofthe information carrier so as to render possible a communication betweenthe chip and the playback apparatus.

Communication means rendering possible this communication are present inthe playback apparatus. The communication means in the apparatus areformed, for example, by an integrated circuit, a so-termed read-out IC,and an antenna. The communication means in the existing system aredesigned such that communication can take place between the chip on theinformation carrier and the read-out IC in-the apparatus only if theinformation carrier is present inside the apparatus.

It is a disadvantage of the known apparatus that the communicationbetween the chip and the read-out IC can only take place when theinformation carrier is present in the playback apparatus.

It is an object of the invention to provide an apparatus of the kindmentioned in the opening paragraph which renders possible acommunication between the chip and the read-out IC which is not limitedto a fixed position of the information carrier in the playbackapparatus.

This object is achieved in that the communication means are constructedsuch that the communication between the integrated circuit and theapparatus can take place both when the information carrier is presentinside the apparatus and when the information carrier is present in thevicinity of the apparatus.

The invention is based on the recognition that it is favorable in somecases to render possible a communication with the chip on theinformation carrier also in the vicinity of the playback apparatus. Theinformation stored in the chip may be, for example, the table ofcontents of the information carrier. If the stored digital workcomprises, for example, music albums, such an information carrier willquite probably comprise dozens of titles. It would be very convenientfor the user of the system if he/she could read the table of contents byjust holding the information carrier close to the playback apparatus.The communication means in the playback apparatus may then display thisinformation, for example, on a screen. The user can obtain the desireddata easily and quickly in this manner.

In an embodiment of the apparatus according to the invention, thecommunication means of the apparatus comprise at least two antennas. Oneof these antennas is present, for example, on the pressure body of theplayback apparatus. This position renders it possible for the chip onthe information carrier to be read when the information carrier isinside the apparatus. A further antenna will then be located, forexample, on or adjacent an outer wall of the apparatus. The location ofthis antenna renders it possible to communicate with the chip alsooutside the apparatus.

An embodiment of the apparatus according to the invention ischaracterized in that at least two antennas are coupled to one read-outIC.

The advantage of this measure is that the cost of the communicationmeans present in the apparatus can be reduced.

In the prior-art system, the communication means in the playbackapparatus comprise one read-out IC connected to one antenna. These meansare capable of achieving an electromagnetic coupling with an antenna onthe information carrier. If a second antenna is desired in theapparatus, for example for reading the table of contents without havingto load the information into the apparatus, it would seem logical to usean additional read-out IC connected to an additional antenna. Theembodiment is based on the recognition that the cost of thecommunication means can be reduced in that one read-out IC is used, towhich two antennas are coupled.

These and further aspects of the apparatus according to the inventionwill be explained in more detail below with reference to drawings, inwhich:

FIG. 1 is a diagrammatic plan view of an embodiment of the informationcarrier,

FIG. 2 is a diagrammatic cross-sectional view of the embodiment of theinformation carrier taken on the line II-II in FIG. 1,

FIG. 3 is a diagrammatic elevation of a system comprising an apparatusfor reading the information carrier,

FIG. 4 is a diagrammatic elevation of an embodiment of the apparatus,

FIG. 5 is a circuit diagram of the communication means of the apparatusand the chip and antenna on the information carrier, and

FIG. 6 is a circuit diagram of an embodiment of the apparatus accordingto the invention.

Furthermore, the mutual dimensional ratios of the components have notbeen necessarily exactly depicted in the Figures for reasons of clarity,where applicable. It will be clear to those skilled in the art thatalternative but equivalent embodiments of the invention are possiblewithout departing from the essence of the invention, and that the scopeof the invention is limited by the claims only. Thus the embodimentsdescribed below relate to an information carrier with an integratedcircuit, such as a DVD. It will be obvious that the principles of theinvention may be equally well applied to other rotating informationcarriers such as CD-R, CD, DVD+RW, CD-I, and other members of the familyof optical information carriers. It will also be obvious to thoseskilled in the art that the description given below of embodiments of aplayback apparatus is also applicable to a recording apparatus forwriting on the optical storage unit.

FIG. 1 shows the information carrier that can be read out by theapparatus according to the invention. The information carrier in thisexample is a disc with an optically readable storage unit. Theinformation carrier 1 is provided with a center hole 11 situated in thecenter of the disc. Several areas are defined on the information carrier1, furthermore, which areas may each have, for example, differentphysical properties. The disc comprises a clamping area 12 which is usedfor clamping the disc between two bodies. This clamping renders itpossible for the disc to move and rotate about the center of the disc ina contactless manner. This will be described in more detail below whenthe system is discussed. Furthermore, an information area 13 is definedon the disc, where the optically readable storage unit is present. Thisstorage unit comprises a track which is arranged in a spiraling orconcentric pattern. It is possible to read the track on the informationcarrier by means of a read head known to those skilled in the art. Theread head comprises inter alia an optical system for focusing a lightbeam, for example generated by a laser diode. The optical storage unitis built up from several layers, among them a polycarbonate layer and ametal layer. A transitional region 14 is present between the clampingarea 12 and the information area 13. The transitional region 14 is alsoconstructed with the polycarbonate layer and the metal layer in theprior art. The transitional region 14 is denoted the CiD regionhereinafter.

The optical information carrier 1 further comprises an integratedcircuit 21 and an antenna 22 which is connected to the integratedcircuit (denoted chip hereinafter) 21. An embodiment of the informationcarrier with the chip and the antenna shown in the CiD region can beseen in FIG. 2. The antenna is preferably a coiled antenna. The antennais always located in the CiD region. There are no limitations as to thepositioning of the chip, for example, it is possible to position thechip in the information area, but the CiD region is preferred. The chipis, for example, a MiFare RFID chip manufactured by Philips ElectronicsN.V. and is also described in the RFID HANDBOOK, p. 282 by KlausFinkenzeller, published by John Wiley & Sons.

The chip provides the possibility of storing information. Thisinformation may be, for example, a decoding key for decoding the digitalwork stored in coded form on the information carrier. The illegalcopying and distribution of the digital work on the information carrieris rendered more difficult through the provision of the decoding keys ina separate memory, and not on the information carrier itself. Anotherexample of the use of the storage capacity in the chip is the storage ofa table of contents. This table of contents may comprise all titles andperforming artists of musical numbers stored on the information carrierin the case in which the digital work comprises, for example, aplurality of music albums. This information in the chip may then be readout, for example, and displayed on a screen.

The chip and the antenna are capable of achieving an electromagneticcoupling to another antenna connected to a read-out IC in a playbackapparatus, as will be explained in more detail in the discussion of thesystem.

To promote the communication between the chip on the disc and theread-out IC, no metal layer is present in the CiD region. The metallayer is shown hatched in the plan view of an embodiment of theinformation carrier in FIG. 1. No eddy currents interfering with theelectromagnetic coupling will arise because no metal layer is presentadjacent the antenna.

FIG. 2 is a diagrammatic cross-sectional view of the first embodiment ofthe information carrier taken on the line II-II in FIG. 1. The opticalinformation carrier in this embodiment is in the form of a DVD. As isknown to those skilled in the art, the layered structure of this disc issuch that pits and lands are formed in the polycarbonate layer 31. Thebinary data are encoded in these pits and lands. A reflecting metallayer 32 is laid over this polycarbonate layer. This combination oflayers has a thickness of 0.6 mm. An additional polycarbonate layer 33is provided on top of these layers for obtaining an additional strengthand protection.

The antenna 22 is located in the CiD region 14 and is provided at theupper side of the disc. Although this embodiment is preferred because ofthe comparatively simple adaptation of the production process of opticalinformation carriers, it is alternatively possible to provide theantenna between the layers of the disc. The antenna is then shaped inthat a continuous metal layer is sputtered, from which the antenna wiresare cut out by means of laser technology. The provision of the antennaon top of the disc may take place, for example, by means of a sticker.Conductive current wires are positioned in a coiled pattern on anadhesive layer and then fastened to the disc. These conductive wiresform the antenna and are directly connected to the chip on theinformation carrier. As will be apparent to those skilled in the art,the antenna may alternatively be fastened to the lower side of theinformation carrier, i.e. the same side from which the optical storageunit is also read.

The metal layer 32 is present in the information area and not in the CiDregion. This promotes the communication between the chip and theread-out IC. Since no metal layer is situated adjacent the antenna, noeddy currents will arise which interfere with the electromagneticcoupling.

As those skilled in the art will understand, the same principle may beapplied to other optical information carrier families such as the CDfamily and the DVR family, in which the metal layer is at differentlevels in the disc.

FIG. 3 is a diagrammatic cross-sectional view of an embodiment of asystem comprising the information carrier and an apparatus. Theapparatus comprises inter alia reading means (not shown), for example aread head for reading out information from the optical storage unit. Theapparatus further comprises a carrier body 61 on which the informationcarrier 1 can be laid. A pressure body 62 is subsequently fastened onthe information carrier 1 so as to clamp the information carrier. Thecarrier body has a shaft that is passed through the center hole of theinformation carrier 1. The pressure body is fastened to the shaft of thecarrier body. In this configuration, therefore, the information carrieris between the carrier body 61 and the pressure body 62. The informationcarrier makes contact with the carrier body and the pressure body in theclamping area of the information carrier. The pressure body ispositioned in a bridge 63 in which it can move freely in the directionof the carrier body and can rotate about the axis of the carrier body.Furthermore, the apparatus comprises an electric motor 64 which isfastened to the carrier body and is arranged such that the informationcarrier 1 rotates in the apparatus, as is known to those skilled in theart.

The apparatus further comprises communication means for establishing anelectromagnetic coupling with an information carrier 1 provided with anantenna and a chip as described above and shown in FIG. 1. Thecommunication means of the apparatus comprise a read-out IC 65 andanother antenna 66. The read-out IC is, for example, a MiFare RFIDReaderIC manufactured by Philips Electronics N.V. and is also describedin the cited RFID HANDBOOK by Klaus Finkenzeller. This ReaderIC operatesat 13.56 MHz, which corresponds to a wavelength of the electromagneticwaves of approximately 22 m. Since the distance between the two antennasis many times smaller than 22 m, all may be regarded as magnetic flux.The antenna 66 of the communication means in the apparatus is connectedto the ReaderIC and has a coil-type or concentric character.

The antenna 66 of the communication means of the apparatus is preferablyarranged perpendicularly above the antenna on the information carrier soas to obtain an optimum coupling. This coupling must be achieved interalia when the information carrier is in the apparatus and the opticalstorage unit of the information carrier is being read out. The antennain the apparatus may be fastened, for example, to the bridge 63perpendicularly above the antenna on the information carrier as shown inFIG. 6. It will be clear to those skilled in the art that alternativeembodiments are also possible.

FIG. 4 diagrammatically shows how the playback apparatus 4 is equippedwith two antennas 66 connected to at least one read-out IC 65. Thesecond antenna 66 is located such that it is possible to read out thechip on the information carrier through electromagnetic coupling whenthe information carrier is outside the apparatus. The second antenna isprovided, for example, at the upper side of the apparatus or at thelateral side thereof, as shown. It is sufficient then to hold theinformation carrier in the vicinity of the antenna for reading of, forexample, the table of contents stored in the chip. In an embodiment ofthe invention, the second antenna has two turns of 70 mm diameter. Theantenna on the information carrier has a diameter of approximately 40 mmwhen it is placed in the region between the clamping area and theinformation area. The larger diameter of the second antenna providingfor communication between the apparatus and the chip on the informationcarrier outside the apparatus creates a larger area in which it ispossible to read out the chip. If the MiFare chip mentioned above isused, it is possible to realize an electromagnetic coupling over adistance of a few centimeters between the antenna in the apparatus andthe antenna on the chip, and thus to communicate.

The placement of the second antenna is not bound to a fixed location. Itis possible to place the antenna in any position adjacent the peripheryof the apparatus. In an embodiment of the invention, there is no metalbetween the second antenna and the periphery of the antenna. This hasthe advantage that the communication between the antennas is promoted inthat no eddy currents arise because of the absence of the metal layer.

FIG. 5 is a circuit diagram of the communication means of the apparatusand the chip and antenna on the information carrier. As is known tothose skilled in the art, a current changing in time through a firstcoil will generate a magnetic flux which also changes in time. Theinductance law states that a voltage will be induced in the first coil,but also in a second coil if the latter comprises a portion of thegenerated magnetic flux.

The changing magnetic flux in the antenna 66 connected to the read-outIC 65 induces a voltage in the antenna 22 connected to the chip 21 onthe information carrier 1 owing to the mutual induction. Communicationcan thus take place between the chip on the information carrier and theread-out IC in the apparatus by means of electromagnetic coupling.

An embodiment of the apparatus according to the invention is shown inFIG. 6. The communication means of the apparatus are now constructedsuch that they comprise two antennas, one for communication when theinformation carrier is present inside the apparatus, and one forcommunication when the information carrier is adjacent the apparatus.These two antennas are coupled to one read-out IC. This embodiment hasthe advantage that the cost of an extra read-out IC is saved.

1. An apparatus for reading out an information carrier, whichinformation carrier is provided with an integrated circuit and anantenna connected to the integrated circuit, said apparatus beingprovided with communication means for achieving an electromagneticcoupling with the antenna on the information carrier, characterized inthat the communication means are constructed for achieving communicationbetween the integrated circuit and the apparatus when the informationcarrier is present inside the apparatus and for achieving communicationbetween the integrated circuit and the apparatus when the informationcarrier is present in the vicinity of the apparatus.
 2. An apparatus asclaimed in claim 1, characterized in that the communication meanscomprise at least two antennas, one for communication when theinformation carrier is inside the apparatus and one for communicationwhen the information carrier is present in the vicinity of theapparatus.
 3. An apparatus as claimed in claim 2, characterized in thatat least two antennas are coupled to one read-out IC.
 4. An apparatus asclaimed in claim 3, characterized in that the two antennas are connectedin series and coupled to the read-out IC.
 5. An apparatus as claimed inclaim 2, characterized in that the housing of the apparatus is at leastpartly free from metal at the area of the antenna for communicationbetween the chip and the apparatus when the information carrier is inthe vicinity of the apparatus.